Detection and Identification of Rickettsial Agents in Ticks From Domestic Mammals in Eastern Panama

Abstract

Several outbreaks of Rocky Mountain spotted fever have occurred in recent years in Colombian communities close to the border with Panama. However, little is known about rickettsiae and rickettsial diseases in eastern Panamanian provinces, the Darien Province and the Kuna Yala, located north of the endemic area in Colombia. In 2007, 289 ticks were collected in several towns from dogs, horses, mules, cows, and pigs. DNA was extracted from 124 Dermacentor nitens, 64 Rhipicephalus sanguineus, 43 Amblyomma ovale, 35 A. cajennense, 10 Boophilus microplus, 4 A. oblongoguttatum, and 9 A. cajennense nymphs. SYBR-Green polymerase chain reaction assays targeting a fragment of the OmpA and 16S rRNA genes were used for detection of DNA of the spotted fever group rickettsiae (SFGR) and Anaplasmataceae (Anaplasma and Ehrlichia), respectively. In total, 37.4% ticks were positive for SFGR, including 20.3% R. sanguineus, 27.9% A. ovale, 25.8% D. nitens, 50% B. microplus, 50% A. oblongoguttatum, and 100% A. cajennense. The presence of Rickettsia amblyommii DNA was confirmed by sequencing in A. cajennense, A. oblongoguttatum, A. ovale, B. microplus, and R. sanguineus. DNA of R. rickettsii was only detected in one D. nitens collected from a horse in Santa Fe, Darien Province. Prevalence of Anaplasmataceae varied from 6.3% in R. sanguineus to 26.5% in A. cajennense. DNA of Ehrlichia chaffensis was found in three D. nitens and three A. cajennense from horses. This is the first study providing molecular characterization and prevalence information on SFGR in ticks from these areas and thus will be helpful for future evaluations of the risk of rickettsial diseases for individuals living in this region.

Distribución de los ectoparásitos de Canis lupus familiaris L. (Carnivora: Canidae) de Panamá

“…In Panama, genetic material of R. amblyommii has been found in R. sanguineus (14), species implicated to cause a mild fever, even when its impact to humans is unknown in many counties.…”

Ticks (Acari: Ixodidae) infesting wild birds in the eastern Amazon, northern Brazil, with notes on rickettsial infection in ticks

“…Different strains of this Rickettsia have been reported infecting at least five Amblyomma species from the USA to Argentina, including A. longirostre from the state of Rondônia, western Brazilian Amazon, and from the state of São Paulo, southeastern Brazil (Bermúdez et al 2009;Labruna et al 2004cLabruna et al , 2007bOgrzewalska et al 2008;Parola et al 2007;Weller et al 1998). While R. amblyommii is not currently recognized as human or animal pathogen, there has been serological evidence for human and canine infection by this agent in the USA and in the Brazilian western Amazon, respectively (Apperson et al 2008;Labruna et al 2007c).…”

Update on Tick-Borne Rickettsioses around the World: a Geographic Approach

“…Epidemiologically important vectors of R. rickettsii in North Haemaphysalis leporispalustris in Costa Rica, all of which may occasionally be involved in the transmission of this pathogen to humans and animals (51,(72)(73)(74)(75). Contemporary molecular surveys for R. rickettsii in North American Dermacentor ticks reveal extremely low frequencies of occurrence of these bacteria in ticks, characteristically Ͻ0.5% (76)(77)(78)(79)(80).…”

“…Contemporary surveys of questing adult A. americanum ticks collected from several states in the eastern United States reported average infection frequencies of 45% in Georgia, 66% in Maryland, 13% in New Jersey, 42% in New York, and 60% in North Carolina (131)(132)(133)(134). Infections have also been detected commonly in larval-stage ticks (78,127,135,136 (72,139,140). "Candidatus Rickettsia amblyommii" has been implicated as a possible cause of mild or subclinical infection in humans in the United States (137,141); however, neither guinea pigs, meadow voles, nor rabbits exhibit any evidence of disease when inoculated with this SFG rickettsia (130), and there is no evidence of direct detection of "Candidatus Rickettsia amblyommii" in human clinical specimens (142).…”